The present invention generally relates to flexible tubing and, more specifically, to spiral-wound tubing which is flexible.
Tubes are often used as protective coverings such as, for example, over lead wires associated with electric motors and the like. The tubes can protect against many different types of potentially harmful conditions such as preventing abrasion and wear, insulating against heat, and/or insulating against EMF interference.
Often it is desirable for the tubes to have suitable flexibility for forming compound shapes and conforming to the shape of the protected item. Many plastic corrugated tubes are known which provide flexibility. For example, see U.S. Pat. No. 3,908,704, the disclosure of which is expressly incorporated herein in its entirety. These tubes, however, can only be use in a limited number of situations because only a limited number of materials can be used. Additionally, the plastic corrugated tubes are often molded or extruded and therefore are relatively expensive to produce.
Spiral-wound tubes are used in many applications because of the wide variety of materials which can be used and the relatively low cost of production. Such spiral-wound tubes, however, are typically semi-rigid. One approach to make a length of spiral-wound tube some what flexible has been to longitudinally crush it to form numerous generally annular-shaped and nonuniform pleats or corrugations therein. The crushing process, however, adds an additional manufacturing step after the tubes are cut to length which is relatively difficult and expensive to implement. Additionally, the tubes do not provide sufficient flexibility for some applications.
Accordingly, there is a need in the art for improved flexible tubing which can be produced from a wide variety of materials, has a high degree of flexibility, and is relatively inexpensive to produce.